Gas fired unit heater



May 8, 1934. w BELL 1,958,331

GAS FIRED UNIT HEATER Filed March 14, 1932 3 Sheets-Sheet l 35 Wfi-Bell May 8, 1934. w. D. BELL GAS FIRED UNIT HEATER Filed March 14, 1932 5 Sheets-Sheet 2 AAAAAAMFAAAAA May 8, 1934. w. D. BELL GAS FIRED UNIT HEATER Filed March 14, 1932 3 Sheets-Sheet 5 Patented May 8 1934 PATENT OFFICE GAS FIRED UNIT HEATER William Bell, Columbus, Ohimassignor to F. 0. schoedinger, Columbus, Ohio Application March 14, 1932, Serial No. 598,625

Claims.

This invention relates to improvements in gas .fired unit heaters of the type employed in the heating of manufacturing plants, garages, thea- 5 ters, stores, public buildings and the like.

Heaters of this type are usually suspended from the ceiling of rooms they are employed to .heat and embody ordinarily a suspended casing structure provided with a burner box in which is arranged a gas consuming burner. Above the burner box there is provided a plurality of heat radiating fines or elements through which the hot combustion gases, formed in the burner box, are passed, the rear of the casing structure being provided with a fan, driven by an electric motor. The fan functions to force air past the heated exterior surface of the fiues, whereby to heat the air and deliver the same directly into the room. Through such heat interchange, the combustion gases are greatly reduced in temperature so that ture through an outlet ventin the upper part thereof, their temperature is efiiciently low. It is an outstanding feature of heaters of this character that they may be used advantageously wherever ordinary lighting current and heating gas facilities are available, since the heaters are self-contained, and do not require association with remotely disposed heating plants, as is necessitated in previous heaters of this general type using steam as the heating medium.

The principal object of this invention is to provide a simple and eflicient gas fired unit heater of the character set forth wherein the heat developed by the combustion of natural or artificial hydrocarbon gases may be utilized most efiiciently in the heating of the desired room area, this advantage resulting largely by virtue of the cross sectional configuration and interior bafiling of the heat radiating fines or elements, which are so formed that the heated combustion {gases are retained in the fiues for a suflicient period of time to insure proper transfer of their heat to the walls of the fiues'and thence to the positively advanced air current passing over the exterior surfaces of the flues.

It is another important object of the invention to provide for improved automatic control for regulating the operation of the heater. In the ;casing surrounding the heating surface of the heater and immediately in the path of the circulating air from the fan there is provided a thermostatically functioning member which serves to regulate the flow of gas to the burner .mechanism, whereby when the temperature within the heater falls below a predetermined when finally discharged from the casing strucpoint, the gas is automatically turned on to in- .By providing independent thermostatic control ,for the gas burner and the fan motor, the walls of the heating elements or fiues are maintained at temperatures, above the atmospheric temperatures of the room being heated, so that when operation of the fan is initiated, warm air will be delivered to the room instead of cool air, as heretofore.

With these and other objects in view, which will appear as the description proceeds, the invention consists in the novel features of construction, combination of elements and arrangements of parts hereinafter fully described and pointed out in the appended claims.

In the accompanying drawings:

Fig. 1 is a perspective view of a gas fired unit heater constructed in accordance with the present invention;

Fig. 2 is a horizontal sectional view taken through the heater;

Fig. 3 is a vertical sectional view;

Fig. 4 is a vertical transverse sectional view taken through the heater on the plane indicated by the line 4-4 of Fig. 3;

Fig. 5 is a detail sectional view of one of the thermostatic valves;

Fig. 6 is a similar view of another thermostatic valve employed as a safety control in connection with the pilot burner;

Fig. 7 is a similar view of the diaphragm control valve, disclosing the pilot supply take-01f.

Referring more particularly to the drawings, the numeral 1 designates the outer casing of my improved heater which is preferably of light weight, sheet metal construction. Within the casing there is provided a burner box comprising preferably a rectangular casting 2, the bottom .of the casting being open and arranged in registration with a grill 3, permitting of air flow into the interior of the casting. Contiguous to its upper portion, the casting is provided with laterally directed lugs 4 which project through openings provided in the side walls 55 of the casing 1. These lugs rest upon nuts 6 which are threaded on the lower ends of suspension rods 7, the upper ends of the latter being adapted for connection with any suitable overhead support (not shown) such, for example, as the ceiling of a room, cross beam or other similar member.

Arranged in the burner box formed by the casting 2 is a gas burner 8, the inlet end of this burner being provided with the customary air mixer 9, located exteriorly of the casing. A gas supply pipe line leads to the air mixer.

Resting on the upper edges of the casting 2 is a flue casting 11. This latter casting is formed to include a plurality of vertically disposed lines 12. The hot gases of combustion, generated by the operation of the burner 8, pass upwardly through the burner box and thence through the flues 12, the latter being provided interiorly with spaced horizontally disposed bafiles 13 by which the heated gases pass in a somewhat tortuous path through each of the fines before being discharged from the open upper ends thereof, as shown more particularly in Fig. 4.

The adjoining edges of the castings 2 and 11 are flanged as at 14 and secured together by means of the threaded fastening elements 15. Similarly, the upper end of the flue casting 11 is flanged as at 16 for the reception of correspondingly shaped flange provided upon the lower edge of a dome casting l7, fastening elements 18 being employed to unite the casting 1'7 with the flue casting 11. By this construction, the burner box casting 2, the flue casting 11 and the dome casting 17 may be securely united in rigid assembled relationship, but the several castings are readily separable for convenience and economy in manufacture. The dome casting is provided centrally with an outlet vent 19 in the top thereof which registers with an outlet conduit 20 leading to the atmosphere. The dome casting 17 is also provided with horizontally and laterally projecting lugs 22, provided with openings through which the suspension rods 7 pass. The flues 12 are disposed in relatively spaced relationship producing, as shown in Figs. 2 and 3, air passages therebetween, and in these air passages, the exterior walls of the flues are provided with a multiplicity of heat radiating fins 23.

The back of the casing l, as shown in Fig. 4, is provided with an opening 24 and in registration with this opening there is moimted a fan 25 which is carried by the armature shaft of an electric motor 26, the said motor being carried in connection with the back of the casing 1 by means of frame brackets 27. The motor 26 is arranged. as

shown in Fig. 2, in an electrical circuit 28, which includes a thermostatic switch 29. Usually, this switch is arranged in the room area to be heated at some distance from the heater proper and the switch functions to close the circuit 28 when the temperature in the room area falls to a predetermined point, whereby to start the motor 26 and the fan 25, causing a forced passage of air through the openings formed between the tines 12, the forced draft of air serving to rapidly remove heat from the surfaces of said fines, to raise the temperature of the air so contacted and to positively deliver such resulting heated air into the room. Attention is directed to the cross sectional configuration of the fines 12, as shown in Fig. 2, wherein it will be noted that the flues are of substantially diamond shaped cross sectional configuration so that the air passages 30 formed between said flues have in their discharge throats outwardly converging side walls. This construction compensates for the increase in volume due to the heating of the air and minimizes back pressure on the fan structure, serving to insure a high rate of air travel through said passages, the quick removal of heat from the walls of the flues, low waste-gas temperatures and a uniform distribution of heated air over the entire room area under the influence of the heater. The fan 25 may be protected by a cage 31. The outlet conduit 20 may be provided with a back draft hood 32.

To control the automatic operation of the gas burner, the gas supply line 10, which leads from a suitable source of gas supply, is provided with a manually controlled shut-off valve 33. The outlet of this valve communicates with the usual automatic pressure regulator 34, which functions to maintain substantially constant the gas pressure in the line leading from the outlet of the regulator irrespective of pressure fluctuations in the supply line as long as the valve 33 is open.

The outlet of this regulator communicates with a control valve 35 of the diaphragm type, shown in Fig. 7. This valve includes a passage 36 for gas flow which is regulated by a valve member 37 carried by a diaphragm 38. A small port 39 forming a bleed passage is formed in the member 37 for a purpose to be hereinafter explained. The discharge side of the valve 35 leads to the mixer 9 of the main burner. Leading from the inlet side of the valve 35 is a pilot take-off 40 which is provided with a manually regulated valve al. This pilot take-off leads to a pilot 42 arranged in the burner box adjacent to the burner 8 for the purpose of igniting gas flowing from the burn er 8. Usually, the pilot 42 operates to produce a low constant flame, as contrasted with the intermediate high flame of the burner 8.

The bleed chamber 43 of the valve 35 is provided with a bleed line 44 which leads to a thermostatic valve 45, shown in Fig. 5, and which controls the operation of the diaphragm valve 35.

The valve 45 includes a casing provided centrally with a valve seat and which divides the casing into gas inlet and outlet passages. Arranged to engage with the seat is a valve member 45', the stem .6 of which is connected with a thermostatic bar 47 mounted in a tubing 48. The tubing has one end thereof rigidly connected with a base member 49 secured to the outer part of the casing 1. The bar 4"! and tubing 48 extend, as shown in Figs. 3 and 4, into the interior of the casing l. and lie in the path of air travel through said casing and around the flues. When the temperature surrounding the flues reaches a predetermined high degree, expansion of the bar 47 is suficient to effect the closing or the valve member 45, thereby obstructing gas flow through the bleed line a l. This results in an increase in pressure over the diaphragm 38, which actuates the valve member 3'? to close the passage 36 and consequently arrest gas flow through the main supply line to the burner 8. On the other hand, if the temperature adjacent to the fines 12 is sufficiently low, the contraction of the bar 47 results in the opening of the valve 45, thereby causing of cool air to the room area, as would be the case if the flue temperature were permitted to fall to substantially room temperatures. As an additional safety feature, the bleed line 44 is provided with a second thermostatic valve 50, located between the valve 45 and the burner 8 into which the section 44 of the bleed line extends. A valve 50 has its heat sensitive tube 51 located immediately adjacent to the pilot burner 42, so that in the event the pilot burner should be extinguished for any reason, the valve 50 will close, obstructing gas flow through the bleed line and consequently the main line 10 to the burner 8, until the pilot has been relighted.

The front wall of the casing 1, in registration with the flues 12 is provided with an opening 52 formed with vertical sides flanges 53. Adjustable shutters or louvers 54 are pivotally mounted in connection with the flanges 53 and may be positioned to direct the heated air, discharged from the heater in a desired manner into the room area under the influence of the heater. Above the opening 52, the front wall of the easing may be perforated as at 55 to admit of the discharge of heated air from the top internal portion of the casing. One of the side walls of the casing adjacent the bottom of the latter, may be provided with a glazed observation opening 56 by which the operation of the burner 8 may be exteriorly observed or determined.

While I have described what I consider to be the preferred form of the present invention, nevertheless it will be understood that the specific disclosure herein given sets forth but one of several possible embodiments of my invention and therefore I reserve the right to employ all such variations or modifications thereof as may be said to fall within the scope of the following claims.

What is claimed is:

1. In a heating appliance of the character described, an inner casing formedi to comprise burner, flue and outlet sections, a fuel burner mounted in the burner section, a plurality of vertically extending flues formed in the flue section and through which the heated combustion gases from the burner section are passed, a waste gas discharge conduit leading from the outlet section, said flues being relatively spaced to provide therebetween air passages, an outer casing surrounding the inner casing, a fan carried by said outer casing for effecting the positive advance of air through the passages formed between said flues, an electric motor for operating said Ian, an electric circuit including a thermostatic switch for automatically governing the operation of said motor and said fan in response to room temperature variations, a fuel supply line leading to said burner, and a thermostatically operated valve po- 'sitioned in said fuel supply line and responsive to the eflective temperatures prevailing immediately adjacent to said flue section.

2. In a self contained heating appliance, a radiator, a fan for effecting forced passage of air over the exterior surfaces of said'radiator,

- burner.

3. In a self contained heating unit, a casing, a radiator mounted within said casing, a gas burner for heating said radiator, an electric motor driven fan for efiectuating the positive advance of air across the exterior surfaces of said radiator, a gas supply line leading to said burner, an electric circuit including a thermostatic switch responsive to room temperature for governing the operation of said motor and fan, and an independent thermostatic element responsive to the temperature of said radiator for completely controlling the flow of gas to said burner, whereby said radiator may maintain a temperature in excess of room temperature at all times.

4. A self contained heating unit, comprising a burner box, suspension means for supporting said burner box, a radiator mounted on said burner box, a casing enclosing said burner box and radiator, an electric motor driven fan carried by the rear of said casing and disposed to effect a positive advance of air across the ex terior surfaces of said radiator, adjustable shutter devices mounted in connection with the front of said casing for governing the direction of discharge of heated air from said casing, room temperature effected thermostatic means for governing the operation of said motor and fan, and independent thermostatic means responsive to the temperature of said radiator for governing the operation of said burner.

5. In a self contained heating appliance, a radisaid valve.

WILLIAM D. BELL. 

